The present invention relates to semiconductor structures and, more particularly, relates to semiconductor structures which include a cobalt or nickel wetting layer prior to the deposition of an aluminum layer.
Advanced metal gate structures for the 22 nm (nanometer) node and beyond may include an aluminum layer. The fabrication of metal gate structures containing aluminum present structural and fabrication difficulties because of aluminum's affinity for oxygen.
These advanced metal gate structures may be fabricated by a replacement gate process. In a replacement gate process, a polysilicon dummy gate is formed and bracketed with spacers and possibly other materials, the polysilicon dummy gate is removed and then replaced with materials that will form the final gate structure.